circle etoile drawing

function draw_circle(r){
    let k=r, str="";
    while(k>=-r){
        let n = r-Math.round(r*Math.cos(-Math.asin(k/r)));
        let m = r+Math.round(r*Math.cos(Math.asin(k/r)));
        for(let i=0;i<n;i++)
            str+="<span class='hide'>*</span>";
        str+="*";
        if(m!=n){
            for(let i=n+1;i<m;i++)
                str+="<span class='hide'>*</span>";
            str+="*";
        }
        str+="<br>";
        k--;
    }
    return str;
}